1. Field of Invention
This application relates to a latching system, particularly one used on a trailer container chassis, and more particularly to a pneumatic control system for such a latching system.
2. Discussion of the Art
A trailer supply line is provided on a trailer chassis and often used to directly supply compressed air from the compressed air system associated with the tractor for various functions associated with the trailer. For example, the supply line provides air to spring brake chambers and thereby release spring brakes that would otherwise be applied in the absence of the compressed air. Another common function is in association with an air operated latching assembly. Typically, air operated latch chambers are provided with compressed air from the supply line to connect the trailer container to the trailer chassis in a secure manner.
It is also common to employ a separate reservoir system for the trailer. The trailer reservoir system, again, allows a wide array of compressed air systems associated with the trailer to be operated from a reservoir having sufficient capacity to handle multiple tasks. As will be appreciated, the size or volume of the reservoir requires time to charge the reservoir to the desired operating pressure. Thus, compressed air systems on trailers that use the reservoir must account for the possibility that the compressed air will not be immediately available.
Known latching systems used on the trailer container chassis are either supplied by a trailer supply line or, separately, by a trailer reservoir system. Under the first scenario, the supply line feeds the latching network and a loss of the supply line results in the release of the latching mechanism, in addition to a trailer spring brake application. Under the latter system, the trailer reservoir system supplies the compressed air for the latching assembly and could result in an operator inadvertently pulling away with the latching system disengaged. Neither of these scenarios is desirable.
Accordingly, a need exists for an improved latching system for a trailer container chassis that overcomes the various inadequacies noted above.
The present invention provides an improved trailer container latching system that advantageously uses compressed air from the supply line and the trailer reservoir system.
A preferred embodiment of the trailer container latching system includes a supply line adapted for connection with the trailer supply line and a separate, trailer reservoir. A trailer container latching assembly is initially in selective communication with the trailer supply line, and subsequently with the trailer reservoir via a valve, the changeover operative at a predetermined pressure being attained in the trailer reservoir.
The control valve includes a first port connected with the supply line, a second port adapted for connection with the trailer reservoir, and a third port that selectively delivers air pressure to the latching assembly. A separate line interconnects the trailer reservoir and the container latching assembly.
A method of controlling the trailer container chassis latching system includes the steps of initially connecting the supply line to the latching assembly, charging the trailer reservoir, and interconnecting the trailer reservoir with the latching assembly once a predetermined pressure level is reached.
A primary advantage of the invention resides in the ability to ensure that the latch is secured initially upon departure.
Another advantage of the invention resides in the ability to use the trailer reservoir to maintain the latch chamber once the trailer reservoir system is adequately charged.
Still another advantage of the invention resides in the ability to maintain an adequate latching should a failure occur in the trailer supply line after the trailer reservoir system is charged.
Still other advantages and benefits of the invention will become apparent to those skilled in the art upon a reading and understanding of the following detailed description.